X-ray absorbing material and variants

ABSTRACT

The present invention relates to an X-ray absorbing material that can be used in medicine as well as in the manufacture of special protective clothing, protective screens, housings, protective coatings and isolation materials. In a first embodiment, the material uses as a filler a poly-dispersed mixture, segregated by kneading and containing metallic particles having a size between 10 −9  and 10 −3  m, wherein the particles are bonded to the surface of a textile base. The density of the material is defined by the relation q N =(0.01–0.020) q P , where q N  is filler. In a second embodiment, the invention uses as a filler the above mixture, although here the particles are surrounded by the volume of a matrix made of a compound that solidifies under atmospheric pressure. The total mass of the poly-dispersed and segregated mixture is defined by the relation M=(0.05–0.5)m, where M is the total mass of the X-ray absorbing poly-dispersed and segregated filler, while m is the equivalent mass of the filler material that is equal in protective properties to the mass M. In a third embodiment, the invention uses as a filler the above mixture with the particles bonded to an intermediate substrate consisting of a textile base and surrounded by the volume of a matrix.

The application claims priority from PCT/RU98/00301, filed Sep. 24, 1998claiming priority from Russian Application No. 91116386, filed Sep. 30,1997, and the contents of both references are herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to X-ray contrasting and X-ray protectionmaterials and can be used in the field of medicine, namely in Roentgenequipment intended for the diagnosis and management of variousconditions. More specifically, it can be used for the monitoring ofendo-prosthetic appliances, internal surgical joints and connections,and of post-surgical areas of the body in order to avoid leavingsurgical napkins, tampons or surgical instructions inside the body of apatient. The invention can also be used to select areas to be exposed inthe course of radiation therapy, etc., as well as to produce protectiveuniforms (aprons, smocks, waistcoats, caps, etc.) and protectiveshields, partitions, protective coatings, isolation materials, etc.

2. Description of the Prior Art

Already known is an X-ray absorbing material as disclosed in SwedishPatent No. 349366, which provides for an artificial rayon thread thatcontains barium sulfate (BaSO₄) as a mechanical impurity (15% through65% of total mass). However, adding this mechanical impurity to thetextile base of the material results in an abrupt reduction of thematerial's durability.

Also known are X-ray absorbing materials, for example, in the form ofthreads that contain bismuth oxide, colloidal silver, and iodinederivatives—all in the form of X-ray contrasting impurities added to apolymeric composition (see, for example, the X-ray absorbing materialsdescribed in the Abstract of A. V. Vitulsky entitled “Obtaining andresearching of synthetic fibers with X-ray contrasting and anti-germsolutions being added at the time of preparation,” Leningrad, 1974).However, an examination of the properties of a textile base containingsuch impurities reveals that because the homogeneity of the fiberstructure is violated, which is caused by the negative influence ofparticles of contrasting impurity, the physical and mechanicalproperties of the fibers and threads made on the basis of suchimpurities are degraded. A textile base containing such impurities lacksdurability, and this limits the range of applications this base canhave.

Another known example of the prior art is the X-ray absorbing materialdisclosed in the Bulgarian Certificate of Invention No. 36217 (1980),made in the form of a thread containing a protective coating againstX-rays produced from heavy metals that have been derived by means ofcrystallization from corresponding salt solutions. Unlike the materialsmentioned above, this one displays better physical and mechanicalproperties because the derivation of the coating by crystallization ofthe heavy metals from solutions does not substantially affect themechanical properties of the initial material. Nevertheless, thethinness of the coating causes a lessening of X-ray contrasting andX-ray protection properties. Furthermore, after washing, cleaning and soon, the X-ray absorbing coating adheres only weakly to the initialmaterial, and this causes an abrupt reduction of the X-ray contrastingand X-ray protective properties.

Another known example of the prior art is the X-ray absorbing materialdisclosed in Soviet Certificate of Invention No. 1826173 A61

17/56, 17/00, U.S.S.R., (1980), which has the merits of a material inthe form of a thread containing the X-ray absorbing coating of heavymetals, but lacks its drawbacks. This is due to the fact that the X-rayabsorbing coating is made of ultra-dispersible particles (UDPs) of sizesbetween 10⁻⁶ and 10⁻⁷ m and displays such properties as the abnormalweakening of radiation, as stated in “The phenomenon of abnormalreduction of X-radiation by an ultra-dispersible environment” (DiplomaNo. 4 of the Russian Academy of Natural Sciences, priority date—May 7,1987). The metal-containing element (between 10⁻⁶ and 10⁻⁷ m in size), afinely dispersible mixture of this material, is bonded to the surface ofthe thread, i.e., on the surface of the textile base. However, the useof a finely dispersible mixture only in the range of ultra-dispersibleparticles (between 10⁻⁶ and 10⁻⁷ m in size) that are chemically andphysically fissile and pyrophoric, combustible is technologicallyproblematic because it requires special conditions of manufacture,transport, storage and technological application.

The recent discovery in the field of physics of the poly-dispersedenvironment, entitled “The phenomenon of the abnormal alteration bymono- and multiple environments of permeating radiation quantum streamintensity” (Diploma No. of the Russian Academy of Natural Sciences,priority date—Sep. 19, 1996) caused the discovery that thepoly-dispersed environment, assuming that a certain level ofdispersibility of particles and segregation thereof by intermixing isensured, displays a capacity for an abnormally high reduction of X-rayradiation. This is caused by the fact that the poly-dispersed particles,having a size of between one thousandth and hundreds of micrometers,organize themselves into energetically interconnected X-ray absorbinggroups. (“The segregation of poly-dispersed particles” means anirregular distribution of the poly-dispersed particles caused by theintermixing of the mixture that is due to the particles'self-organization into a system of energetically interconnected groups,ensuring an increase in photo-absorption.) It is generally known inmodern engineering that the use of poly-dispersed mixtures that consistof particles having a size of between 10⁻⁹ through 10⁻³ m does notrequire any specific limitations and is not fraught with specifictechnological difficulties in manufacture, transport, storage and use.

U.S. Pat. No. 3,239,669 discloses an X-ray absorbing material containinga rubber matrix with a fixed X-ray absorbing filler. According to thispatent, X-ray absorbing elements in the form of lead, bismuth, silverand tungsten can be used as a filler. The main drawback of this exampleof the prior art is that it reduces the solidity of the material by afactor of two to three times due to the fact that the absorbingparticles of filler have a negative influence by violating the uniformstructure of the original polymeric mass.

U.S. Pat. No. 2,153,889 discloses other X-ray absorbing materials. Thesecontain a matrix with a fixed X-ray absorbing filler or in the form ofgold tubes. U.S. Pat. No. 3,194,239 discloses an X-ray absorbingmaterial in the form of a wire consisting of alloys that contain silver,bismuth, tantalum, wherein the wire and the matrix are fastened togetherby interweaving and forming a kind of textile thread. Materialscontaining a matrix with a fixed X-ray absorbing filler of wire made ofsilver-, bismuth-, tantalum-containing alloys where the wire and matrixare fastened together by interweaving and form a textile thread arepreferable to the materials disclosed in U.S. Pat. No. 2,153,889, withregard to their solidity, but have a lower plasticity. This lowerplasticity is inadmissible in many cases.

Also known are materials that protect from the impact of X-ray and gammaradiation with heavy fillers, the most widespread of which is lead (See“Technical headway in atomic engineering.” In Isotopes in the U.S.S.R.,vol. 1 (72), p. 85). A filler (for example, lead) and a matrix (forexample, concrete, polymers, etc.) differ greatly in density, andtherefore the filler (lead) is spread irregularly along the matrixvolume, which results in a decrease in the X-ray absorbing properties ofthe material as a whole.

United Kingdom Patent No. 1260342, G 21 F 1/10 discloses an X-rayabsorbing material produced on the basis of a polysterol polymericmatrix and a lead-containing organic filler. This material has the samedrawback as the lead-containing fillers described in “Technical headwayin atomic engineering.” cited above—it also shows an irregulardistribution of a heavy X-ray absorbing filler inside the matrix, thematerial of which has a considerably lower density than the material ofthe filler.

Closest to the present invention is Russian Federation Patent No.2053074 G21 F 1/10 of Jun. 27, 1996 (prototype), which discloses anX-ray absorbing material containing a matrix with a fixed X-rayabsorbing metal-containing filler in the form of dispersed particles.The drawback of this material is that the addition of a lead-containingfiller to a textile base results in a reduction of the density of thematerial due to the violation of the uniform structure of the textilebase that in turn limits the possibility of using the material for themanufacture of various protective articles. A material made on the basisof a thread with lead-containing filler cannot be used as an X-raycontrasting material in the practice of medical radiology due to thelead's toxic properties. Furthermore, it is impossible to effectivelyand compactly protect against X-ray and gamma-radiation on the basis ofsuch material as a thread (see Russian Federation Patent No. 2063074),and in this case, in order to use the material made from thread it isnecessary to apply the special technology of dense, multi-layer machineknitting for the manufacture of multipurpose protective textile tissue.In this way, however, because the narrow bundle of quanta by a stratumof material having a width=X weakens exponentially, in compliance withthe described rules set forth in Methods of radiation granulometry andstatistical simulation in research on the structural properties ofcomposite materials (V. A. Vorobiev, B. E. Golovanov, S. I. Vorobieva;Moscow: Energoatomizdat, 1984), there occurs a reduction in radiationintensity:I=Io e^(−μx)  (1)WhereI is the intensity of radiation that passes through a stratum ofmaterial having a width=X,Io is the intensity of the initial radiation,μ is the linear factor of radiation reduction (weakening; the tabularregulated value for each of the X-ray absorbing materials).

Another drawback of this example of the prior art consists of the highpercentage of the metal-containing filler in the total amount of theX-ray absorbing material (a percentage of 66%–89%). This causes anincrease in the mass of X-ray absorbing material as a whole, and, on theother hand, the articles made out of this material and heavy andinconvenient to maintain. Still a further drawback of this example ofthe prior art is the irregular distribution of the heavy filler in thematrix volume.

SUMMARY OF THE INVENTION

The main tasks in developing X-ray absorbing (i.e., X-ray contrastingand X-ray protective) materials are:

-   -   to eliminate the toxicity of the X-ray contrasting material; and    -   to reduce the mass and width of the protective material.

The elimination of toxicity is achieved by means of the application ofnon-toxic fillers (tungsten, for example). On the one hand, the creationof a compactness of protection with the width of the protective materialreduced at the same time that the degree of X-ray and gamma radiation isreduced leads to an increase in the mass of the material protectivelayer caused by the use of “heavy” fillers, i.e., fillers of highdensity. On the other hand, when the X-ray absorbing properties areconserved, the reduction of the density of the protective material makesnecessary increasing its width.

This position can be illustrated with an example of an X-ray absorbingmaterial in the form of a protective textile tissue (a radiologist'sprotective apron, for example) that ensures a level of protectioncharacterized by the reduction factor K=100. It is possible to move fromFormula (1) as follows:K=Io/I=e ^(μx)=100,

from whence it follows that:x=lnK/μ=4,6/μ.

As an example, compare the properties of tissues made of threadscontaining known fillers in the form of non-segregated dispersedparticles of lead (Pb) and tungsten (W). The size of the tissuescompared was set as 10×10 cm. The initial data for comparison are shownbelow, in Table 1.

TABLE 1 Initial Data for Comparison Linear factor of Materials used forthe radiation reduction - Particles' material particles of filler − 1(weakening), μ, cm* density ρ g/sm³ Pb 40.3 11.34 W 50.1 18.7 *NOTE:Radiation source is an X-ray emitting (Roentgen) tube, energy −60 keV.

Using the data shown in Table 1, it is possible to deduce from Formula(2), the values of width X for tissues made of threads with a fillerconsisting of:Pb(X=0,11 cm) and W(X=0,09 cm).Accordingly, the mass of such protective tissues with a volume of10×10×10 will be:For Pb—124,74 g, and for W—168,3 g.

If the mass of a protective tissue using Pb is taken as 1, then(according to the equal protective properties and equal sizes) the ratioof the mass of tissues made on the basis of threads containing Pb and Wwill be 1:1.35.

Thus, it is impossible to obtain the simultaneous reduction of the widthof the protective material and its mass using the prior art and knowntechnologies.

According to the present invention, the tasks that must be achieved aresolved by means of the strategies set forth in the distinctive part ofthe independent claims, as discussed below.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of an X-ray absorbing material comprises a matrixwith a fixed X-ray absorbing metal-containing filler. This material usesas a filler a poly-dispersed mixture that is segregated by intermixing.The mixture contains metallic particles having a size of between 10⁻⁹and 10⁻³ m, while the textile base serves as a matrix. As this takesplace, the particles are bonded to the surface of the textile base, andthe density of the X-ray absorbing material as a whole—with the X-rayabsorbing properties of the material being equal to those of thematerial used to the particles of the X-ray absorbing filler—is definedas follows:ρ_(m)=(0.01–0.20)ρ_(p),

where ρ_(m) is the density of the X-ray absorbing material as a whole,and

ρ_(p) is the density of the material used for the particles of the X-rayabsorbing filler.

In a second embodiment of an X-ray absorbing material comprising amatrix with a fixed X-ray absorbing metal-containing filler in the formof dispersed particles, the material uses as a filler a poly-dispersedmixture that has been segregated by intermixing. This mixture containsmetallic particles having a size of between 10⁻⁹ and 10⁻³ m, wherein themetallic particles are surrounded by the volume of a matrix made of atleast one component that is solidifying under atmospheric pressure or ofa matrix made of the composition that forms the base of this component.As this takes place, the total mass of the segregated poly-dispersedmixture of X-ray absorbing particles of filler is defined as follows:M=(0.05–0.5) m,

where M is the total mass of segregated poly-dispersed mixture of X-rayabsorbing particles of filler, and

m is the equivalent mass of the X-ray absorbing filler material equal inprotective properties to mass M.

In a third embodiment of an X-ray absorbing materials that is comprisedof a matrix with a fixed X-ray absorbing metal-containing filler in theform of dispersed particles, the material uses as a filler apoly-dispersed mixture that has been segregated by intermixing and thatcontains metal particles having a size of between 10⁻⁹ and 10⁻³ m. Here,the particles are bonded to an intermediate substrate surrounded by avolume of matrix made of at least one compound that is solidifying underatmospheric pressure or a matrix of the composition that forms the baseof this compound. A textile base serves as an intermediate substrate. Amineral fiber can also be used as an intermediate substrate.

The embodiments set forth above related to a range of inventions thatare all interconnected by the inventors' common conception. In this way,this range of inventions consists of a single type and application, onethat ensures the same technical result, namely, the elimination oftoxicity in an X-ray contrasting material and the reduction of mass andwidth in a protective material, which are all necessary requirements forthe invention that is represented by these embodiments.

The various embodiments of the three presented embodiments of thepresent invention can be explained in a more detailed way as follows.

In a first embodiment of the X-ray absorbing material, a filler iscreated in the form of a poly-dispersed mixture that has been segregatedby intermixing. The fact that this mixture is comprised of metallicparticles having a size of between 10⁻⁹ and 10⁻³ m ensures that theX-ray absorbing filler will evidence the filler's qualitatively newfeature: an increase in the filtering of interaction between the X-rayand gamma ray emissions and substances. Due to this effect, the materialdemonstrates a capacity for increased X-ray absorption.

The use of poly-dispersed mixtures as filler is much used in the X-rayabsorbing materials described in Russian Federation Patents No. 2063074and 2029399, where non-segregated particles with a size between 10⁻⁶ and10⁻³ m are used. However, in this invention these particles are used tocause the more regular distribution of the X-ray absorbing filler alongthe surface of a matrix or inside it.

In the X-ray absorbing metal-containing material defined in the presentinvention, the poly-dispersed mixture that has been segregated byintermixing ensures not only the more regular distribution of the X-rayabsorbing filler along or inside the surface of a matrix but alsoprovides for the evidencing of a qualitatively new effect: an increasein the reduction of the interaction between the X-ray and gamma-rayemissions and substances.

A finely dispersible mixture of metal-containing elements (sized between10⁻⁶ and 10⁻⁷ m) is used in the known material employed in SovietCertificate of Invention No. 1826173. This mixture is bonded to thetextile base surface. Unlike this material, this present invention usesa poly-dispersed mixture made of particles having a wide range of sizes:the range of 10⁻⁹ and 10⁻³ m is used. Thus, particles having sizeswithin the above mentioned range are included within the common mixture.Consequently, there seem to be no technological obstacles to workingwith such a mixture under standard, natural conditions, i.e., themixture does not demonstrate physical and chemical activity. Inparticular, this mixture does not manifest pyrophoric/combustibleproperties.

In the present invention, the use of a poly-dispersed mixture that hasbeen segregated by intermixing and having sizes in the range of 10⁻⁹ and10⁻³ m provides for a qualitatively new effect, if compared with theanalogous material used in Soviet Invention No. 1826173. This effectsconsists in obtaining the same abnormal X-ray absorbing properties.

The dispersed particles of the analogous material of Certificate ofInvention No. 1826173 are bonded to the thread surface, i.e., to thesurface of a textile base. In contrast, in the present invention notonly threads but also separate filaments of a thread can be used as atextile base—i.e., the notion “textile base” includes not only threadbut also separate filaments. The present invention shows separatefilaments to be coated by an X-ray absorbing filler. Furthermore, thesefilaments do so in the form of a poly-dispersed mixture that has beensegregated by intermixing and that contains poly-dispersed particlesself-organized into energetically interconnected power-consuming groups.Provided that the filaments twist into a thread, that thread shall havequalitatively new and higher specific X-ray absorbing properties incomparison with the material in the Soviet Certificate of Invention No.1826173.

Therefore, the use of a textile base as a matrix, where the X-rayabsorbing, metal-containing segregated particles of filler are to thesurface thereof, ensures a qualitatively new effect, one that differsmarkedly from the prior art and is manifested in the higher X-rayabsorbing properties of the material, which is characterized by extremeheightened specific properties of X-ray absorption.

In Soviet Certificate of Invention No. 1826173, an X-ray absorbingcoating of a thread-matrix surface is provided. The X-ray absorbingmaterial offered by the present invention the matrix can be formed bynot only a textile base in the form of whole thread, but also a textilebase in the form of the separate filaments of which the thread consists(as mentioned above). A thread made and twisted from separate filamentseach coated with an X-ray absorbing filler displays much greater X-rayabsorbing properties than a thread where only the open surface thereofis so coated. In the present invention, a filament included in thethread is coated with an X-ray absorbing filler. Moreover, the surfaceof each filament is covered by dispersed particles that have beensegregated by intermixing. As a result, the dispersed particles areself-organized into the energetically interconnected X-ray absorbinggroups and this, in turn, causes the extreme increase in the specificcharacteristics of the X-ray absorbing process.

The embodiment of the X-ray absorbing material as a whole, withsimultaneous X-ray absorbing properties for this material and for thefiller material, can be seen in the following way. If the density of thefiller is defined by the relation:ρ_(m)=(0,01–0,20)ρ_(p),where ρ_(m) is the density of the X-ray absorbing material as a whole;andρ_(p) is the density of the material used to the particles of the X-rayabsorbing filler,then a qualitatively new effect (when compared with the prior artmaterials) is created, namely, the simultaneous reduction of the widthand the density of a protective material, which, in turn, makes itpossible to overcome the main contradiction inherent in the process ofcreating compact protection against X-ray and gamma-radiation. Accordingto the present invention, the densities of the protective materialswithin a thread and tissues, depending on technical conditions, canconstitute between 0.01 (upper limit) and 0.2 (lower limit) of thematerial density of the X-ray absorbing filler particles. If the mass ofX-ray absorbing material (in the present embodiment, a protective tissuemade from a thread, according to the present invention) is taken to be1, then if the protective properties and the sizes of the conventionalprotective tissue to be compared is equal to those of the tissue basedon the thread of the present invention, and under the conditions setforth in Table 1, the correlation by mass will be defined as in Table 2,below.

TABLE 2 Comparative correlation of tissues by mass at equal protectionproperties (with regard to the data set forth in Table 1) Relativelimits of oscil- lation of correlation between the density of tissuemade of the Tissue Tissue made Tissue made material of the present madeof the of threads of threads invention and the density material with afiller with a filler of the material used for of the in the form of inthe form of the particles of the X-ray present non-segregatednon-segregated absorbing filler invention particles of Pb particles of WUpper limit (0.01) 1 198 267 Lower limit (0.2) 1 9.9 13.35Thus the X-ray absorbing material (tissue) of the present inventionwould have a mass between 9.9 and 267 times (all other physical andchemical parameters being equal) when compared with the protectivetissues based on threads with a filler of non-segregated particles of Pband W. This factor ensures a qualitatively new effect.

In consequence, when compared with the prior art, the X-ray absorbingmaterial of the present invention demonstrates the absolute absence oftoxicity, ensures a great deal of solidity equal to the solidity of theX-ray absorbing textile base shown above. Furthermore, the presentinvention ensures abnormally high X-ray absorbing properties with aconcomitant low density.

In a second embodiment of X-ray absorbing material, the use ofpoly-dispersed mixture segregated by intermixing, one comprised ofmetallic particles having a size between 10⁻⁹ and 10⁻³ m (as in theembodiment set forth above), ensures the manifestation of aqualitatively new effect in cutting down the interaction between X-rayand gamma-ray emissions and substances.

First, the poly-dispersed mixture with metallic particles sized between10⁻⁹ and 10⁻³ m are placed inside a matrix volume, where the matrix iscomposed of either at least one component that solidifies underatmospheric pressure or a composition formed on the basis of thatcomponent. The energetic X-ray absorbing groups formed by intermixingand creating a segregated poly-dispersed mixture should not be violatedin any way. This promotes the self-organization of the energetic X-rayabsorbing groups.

An inorganic glue can be used as a matrix. Suggested glues include: Nasilicate and K silicate water solute, or water suspension ofcompositions containing oxides of alkaline metals and earth metals, aswell as compositions made on the basis of such glues.

The natural polymers can also be used as a matrix. These include:collagen, albumin, casein, gum, wood pitch, starch, dextrin, latex,natural caoutchouc, gutta-percha, zein, soy casein, as well ascompositions made on the basis of such polymers.

Synthetic polymers, such as polyakrylates, polyamides, polyethylenes,polyethers, polyurethanes, synthetic rubber, phenolformaldehyde, resin,carbomid resins, calibration epoxy and compositions based on suchpolymers can also be used as matrices.

Element-organic polymers—including silicon-organic polymers,boron-organic polymers, metal organic polymers and compositions based onsuch polymers—can also be used as matrices.

Plastics filled with gas, such as foam plastic and expanded plastic, canbe used as matrices.

Vegetable oils or drying oils can be used as matrices.

Solutions of film-generating substances, such as oily, alkyd,ether-cellulose lacquers, can be used as matrices.

Concrete, gypsum and so on can be used as matrices.

The present invention as defined herein, uses a matrix made of acompound that solidifies under atmospheric pressure, i.e., under naturalconditions. In contrast, in the material in the prior art of the RussianFederation patent No. 2063074, the matrix solidifies under a pressure of150 mPa. In the present invention the mixture does not need to undergopressure as do the protective rubbers described in Russian FederationPatent Nos. 2077745, 2066491 and 2069904, which all underwentvulcanization under pressure after the preparation of the mixture. Theavoidance of high-pressure treatments helps to avoid the destruction ofthe energetic X-ray absorbing groups that are formed in the course ofintermixing X-ray absorbing element particles in a segregatedpoly-dispersed mixture. The present invention distinguishes itself inthe same way from Soviet Certificate of Invention No. 834772, asaccording to that Certificate, the X-ray absorbing material is obtainedunder a pressure of 150–200 kg/cm².

In a similar material in U.S. Pat. No. 3,194,239, the pressed pills ofpreviously crumbled-up iron-manganese (IMC) are used as an X-rayabsorbing filler, which differs from the present invention. The effectof pressure on the filler used in Russian Federal Patent No. 20293399also makes it impossible for the energetic groups to self-organize, asthey do in the present invention. Thus, the present invention, having amatrix of at least one compound that solidifies under atmosphericpressure, or of compositions based on this compound, displays essentialdifferences from the material used in the prior art as defined inRussian Federation Patent No. 2063074.7, and from the similar materialfound in Russian Federation patent Nos. 2029399, 2077745. 2066491 and2069904, with respect to their particular functional properties.

Let us assume a condition, in which the common mass of the segregatedpoly-dispersed mixture consists of the material formed of X-rayabsorbing filler particles. Define this condition by the relation:M=(0.05–0.5) m,where M is the total mass of segregated poly-dispersed mixtureconsisting of the X-ray absorbing particles of filler; andm is the equivalent mass of the X-ray absorbing filler material, whichis equal in protective properties of mass M.

This condition will allow (according to the second embodiment of theX-ray absorbing material) the reduction of the mass of known X-rayabsorbing fillers in protective materials by a factor of 2 to 20 times,depending on the particular technology and at a savings in the X-ray andgamma-ray radiation reduction factor.

Reduction of the mass and the width of the protective material can beregarded as the main objective in constructing protection from Roentgen-and gamma-radiation. The fact that compact protection displays adiminished layer thickness leads to an increase in the protective layermass due to the usage of known heavy fillers. In contrast, saving theRoentgen- and gamma-radiation reduction factor by lowering the densityof the material makes necessary increasing the width of protection. Thisis the main dilemma that arises in attempting to create effectivecompact protection from Roentgen- and gamma-radiation, as thesimultaneously reduction of both width and mass in an X-ray absorbingmaterial practically cannot be achieved with the known fillers used forprotection. This dilemma requires a compromise approach in the choice ofprotective width and mass, also allowing for the cost of suchprotection.

This problem can be illustrated with an example of a common materialused for the purpose of protecting against gamma-radiation, such asconcrete. The density of different sorts of the usual Portland concrete,which contains cement as a connecting substance and silicon shingle,gravel, quartz sand and similar mineral fillers, is 2.0–2.4 g/cm³. Thelinear gamma-radiation reduction factor is 0.11–0.13 cm⁻¹ (for energylevels of 1–2 MeV). Protection made of concrete having such a density isquite cumbersome and should have considerable width. Concrete thatcontains cement as a connecting substance, sand as a filler and galenaas an X-ray absorbing filler in a ratio of 1:2:4 has a density of 4,27g/cm³ and a linear reduction factor 0.26 cm⁻¹(for energy levels of 1.25MeV). With concrete-containing cement as a connecting substance, sand asa filler and lead as an X-ray absorbing filler in a ratio of 1:2:4 andhas a density of 5.9 g/cm³ and a linear reduction factor 0.38 cm⁻¹ (forenergy levels of 1.25 MeV). The protective material made of concretewith a lead filler (leaden fraction) or galena is more compact, but suchprotective material is much more expensive than the usual concretes.

An X-ray absorbing filler such as the baryta BaSO₄ makes possible theresolution of choosing an appropriate width and mass of protectivematerial, while allowing for its cost. However, the appropriate solutionin each case can only be found in a clinical setting. The baryteconcrete, which contains as fillers sand and gravel, and the baryta asan X-ray absorbing filler, has a density of 3.0–3.6 g/cm³. The linearreduction is thus 0.15–0.17 cm⁻¹ (for energy levels of 1.25 MeV).However, the total mass of the baryte concrete protection of setgamma-quantum energy values remains considerable, which causes seriousdifficulties in creating protective material, especially in theprotection of transport facilities.

The above dilemma could be overcome if iron-manganese concretes were tobe used as an X-ray absorbing filler, for example, as disclosed inRussian Federation Patent No. 2029399. But even in this case it isimpossible to reduce the total mass of the protective material by morethan 20–45%, as compared with known and conventional materials.

According to the present invention, however, the correlation that existsbetween the total mass of segregated poly-dispersed mixture consistingof particles of an X-ray absorbing material and the formula set forthabove allows for the reduction of the mass of the known X-ray absorbingfillers included in protective materials up to 2 to 20 times, dependingon particular technical conditions and with savings in X-ray andgamma-ray radiation reduction.

The technical outcome of the second embodiment of the invention is thatan X-ray absorbing material with a low percentage of a metal-containingX-ray absorbing filler is obtained. This provides for the reduction ofthe width and mass of the X-ray absorbing material as a whole withoutthe loss of any X-ray absorbing properties.

In a third embodiment of an X-ray absorbing material, the use of apoly-dispersed mixture that has been segregated by intermixing, onecomprising metallic particles having a size between 10⁻⁹ and 10⁻³ m as afiller (as has been described), makes possible the qualitatively neweffect of the X-ray absorbing filler used, namely, a substantialdiminishment of the interaction between the X-ray and gamma-rayemissions and substances.

The bonding of a segregated poly-dispersed mixture, of the X-rayabsorbing substrate particles to the intermediate substrate, promotesthe ability to obtain an X-ray absorbing material with the evendistribution of heavy X-ray absorbing metal-containing filler inside thematrix having considerably smaller density that the material of thefiller.

The distribution of this poly-dispersed mixture comprised of metallicparticles having a size between 10⁻⁹ and 10⁻³ m inside the volume of amatrix made of at least one compound that solidifies under atmosphericpressure or made of a composition based on said compound eliminates (aswas described above) the possibility that there will be a violation ofthe energetic X-ray absorbing groups that consist of the poly-dispersedmixture of the X-ray absorbing element particles. This distribution alsopromotes the self-organizing of energetic X-ray absorbing groups.

A textile base and a mineral fiber can be used as an intermediatesubstrate according to the third embodiment of the invention.

The above description of embodiments of an X-ray absorbing materialconfirms the possibility that the invention can be realized in practice,since only resources known at the time of the invention's creation areused. In addition, it is shown above that the totality of componentsdescribed as the essence of the invention is sufficient for the solutionof the task at hand.

The above embodiments of the invention can be illustrated with thefollowing examples.

EXAMPLE 1

A filler in the form of a poly-dispersed mixture segregated byintermixing, made of tungsten particles, is bonded to a matrix surfacemade in the form of a twisted lavsan thread. For this purpose, a threadis put for 10 minutes into a pseudo-liquefied (boiling; under the effectof a heavy air stream) stratum of a poly-dispersed mixture. This mixturehas the following proportional structure: 20 microns—15%; 45microns—80%; 500 microns—about 5%; 1000 microns—0.01%.

Under these conditions the segregation of particles occurs because ofthe fact that these particles organize themselves into interdependentpowerful X-ray absorbing groups. At the same time, these particles areattracted to the thread and are therefore “welded” to its surface. Thethread, thus treated, gains the properties necessary for providing anabnormal reduction of X-ray radiation.

The initial data of the experiment:

-   -   Diameter of the thread—0.3 mm;    -   Length of the thread—3200 mm;    -   Weight of the thread before determining the level of mechanical        impurity from tungsten—0.110 g;    -   Width of the thread after determining the level of mechanical        impurity from tungsten—0.160 g;    -   Solidity of the thread before determining the level of        mechanical impurity from tungsten—47 H,    -   Solidity of the thread after determining the level of mechanical        impurity from tungsten—47 H.

Therefore, the mass density of the groups of tungsten particles on thesurface of the thread is 0.0017 g/cm², the size of the thread—0.22 cm³,and the density of the thread, taken as a whole: p=0.7 g/cm³.

After treating the sample of thread with a stream of quanta having anenergy level of 60 keV and after fixing the outcomes on Roentgen film, ameasuring of densities between the standard leaden plates of differingwidths (a gradual weakening from 0.5 mm Pb up to 0.5 with 0.05 Pb) isperformed. As a result, it is ascertained that the X-ray absorptionlevel of the thread is equivalent to a leaden plate having a width of0.1 or 0.075 mm W. Accordingly, this testifies to the abnormally highX-ray absorbing properties of the thread.

Furthermore, according to the claims of the inventionρ_(m)=(0.01–0.20) ρ_(p),

where ρ_(m) is the density of the X-ray absorbing material (in thiscase, a thread) as a whole, and ρ_(P) is the density of the X-rayabsorbing filler material (in this case, tungsten), we have:ρ_(m)/ρ_(p)=0.7/19.3=0.036.

The value obtained for the ratio ρ_(m)/ρ_(p) is within the range of0.01–0.2, which is consistent with the claims of the invention.

EXAMPLE 2

The segregated poly-dispersed particles of tungsten having a sizebetween 10⁻⁹ and 10⁻³ m are bonded to a matrix in the form of a textilematerial (a thick woolen cloth such as that used for an overcoat havinga width of 0,4 cm. The segregation and bonding of the tungsten particlesto the textile matrix occurs due to precipitation due to the presence ofhydrosol under conditions of continuous intermixing for at least thelast 15 minutes. Then a sample is dessicated at room temperature for oneday. The subsequent X-ray testing (at quantum energy levels of 60 keV)shows that the X-ray protection properties of the sample obtainedcorrespond to the properties of a lead slice having a width of 0.015 cm.This level of protection testifies to the abnormally high reduction ofthe X-ray emission stream, since the level of protection in the use of ausual non-segregated filler particle material requires the bonding to amatrix at the level of 100% of the tungsten by mass (instead of the 53%in the present example). Indeed, in the invention according to thepresent example the mass of the X-ray absorbing filler is 0.116 g, i.e.,53% of the total mass of the sample, where the width of a sample made ofa textile material (the thick woolen cloth of an overcoat) is equal to0.4 cm and the size of the sample is 1×1 cm² and the mass thereof is0.216 g. Simultaneously, the density of the X-ray absorbing material asa whole is:ρ_(m)=0.216/1×1×0.4=0.54 g/cm³,and the mass of tungsten in the non-segregated particles is equivalentin its X-ray absorbing properties to:0.015×0.75×19.3=0.217 g,i.e., 100% of the mass of the sample of textile material.

It is obvious from this that the relation ρ_(m)/ρ_(p)=0.54/19.3=0.0279corresponds to the appropriate stated range.

EXAMPLE 3

An X-ray absorbing filler in the form of poly-dispersed particles oftungsten having a size between 10⁻⁹ and 10⁻³ m, the amount=12% of themass, is introduced into a filler in the form of rubber of the brand“Ap-24” having the following structure: C—84.73%; H—9.12%; 5—1.63%;N—0.58%; Zn—2.27%; O₂—1.69% and a size of 100 cm³. The tungstenparticles included in the structure of crude rubber undergo segregationby intermixing in a mixer over the course of 8 hours. As a result, theparticles organize themselves into X-ray consuming groups.

After that the crude rubber, filled with the X-ray absorbing filler,undergoes vulcanization without being put under pressure. Subsequenttesting (at energy levels of quanta of 60 keV) shows that the X-rayprotection properties of the sample of rubber, which has a width of 3mm, correspond to the properties of a lead slice having a width of 0.11mm. This level of protection testifies to the abnormally high reductionin the X-ray emission stream, since the level of protection in the useof non-segregated filler particle material requires adding 0.16 g oftungsten to the matrix, i.e., 34% by mass (instead of 12%, as in thiscase).

Thus, for the example:

-   -   width of a rubber sample—&=0.3 cm;    -   density—p=1.56 g/cm³;    -   a mass of rubber with a size 1×1 cm having 0.468 g; and    -   the total mass of the filler of poly-dispersed particles, i.e.,        12% of the mass of rubber M=0.056 g,        an equivalent mass of X-ray absorbing filler equal in protective        properties to the mass M, is equal to m=0.16 g (34% of the total        mass of the rubber sample).

It is obvious from this that the relation M/m=0.056/0.16=0.35 is wellwithin the range defined in the claims (0.05–0.5). Thus, the amount offiller waste is diminished, the mass of the protection material as awhole is reduced, and production costs are diminished.

EXAMPLE 4

A filler of super-thin basalt fiber TK-4, on which a poly-dispersedmixture that has been segregated by intermixing (in a sphericalporcelain attritor) and that is made of tungsten particles having a sizebetween 10⁻⁹ and 10⁻³ m is fixed, is introduced into a matrix of epoxypriming of the “AP-0010” (Russian Federation Official Standard No.28379-89). The relation of basalt fiber mass to the mass of tungsten is1:3. The proxy priming mixture has been carefully mixed, using a paletteknife, with a prepared basalt fiber so that the relation of the mass ofpriming mixture to the mass of fiber is 1:9. After mixing and obtaininga homogeneous mass, the priming mixture is spread over a surface ofcardboard plates in an even stratum. After solidifying for one day, themixture is tested. The X-ray testing of samples (at energy levels ofquanta=60 keV) shows that at a priming layer depth equal to 2.06 mm, theX-ray protective properties are equal to 0.08 mm Pb. This testifies toan abnormally high reduction of the X-ray emission stream, since theusual level of protection for the use of non-segregated weighingmaterial particles requires adding to the epoxy matrix 38% of tungstenby mass (instead of 7.5%, as in this case).

Consider the example &=2.06 mm, p=1.46 g/cm 3, the mass of an epoxypriming mixture having the size 1×1 cm 2 is 0.3 g. The total mass of anintermediate substrate with tungsten particles bonded to the substrateis 0.03 g (10% of the mixture's mass). Thus, the mass of the tungstenmakes up three-quarters of the mass of the filler, i.e., 0.0225 g, whichconstitutes 7.5% of the mass of the mixture as a whole. Furthermore, themass of tungsten, which is equal to the mass of lead having a width of0.08 mm, is 0.008×0.75×19.3=0.1158 g, which corresponds to 38.6% of themass of the mixture.

EXAMPLE 5

Five percent of the mass of an intermediate substrate in the form ofcrumbled staple fibers (byproducts of fulling and worsted industries)has had poly-dispersed particles of tungsten having a size between 10⁻⁹and 10⁻³ m and having been segregated for 20 minutes by intensive mixingin a pseudo-liquefied layer bonded to it. This five percent is thenintroduced into a matrix of dry gypsum. The relation of the mass ofstaple fibers to the mass of tungsten is 1:3. This mixture is carefullymixed to obtain a homogeneous gypsum-filamentary mass. Water is thenadded and the mixture is carefully mixed again. Samples having a size1×1 cm and a width of 1 cm are cast. After drying and solidifying, thesamples undergo testing (at energy levels of quanta=60 keV). X-raytesting with subsequent matching with gradated lead weakener shows thatthe samples obtained have protective properties equal to those of a leadplate with a width of 0.04 cm. This level of protection testifies to theabnormally high reduction of X-ray radiation, since the same level ofprotection can be attained with the use of non-segregated particles offiller only with a content of tungsten particles of 26.32% of the mass(instead of 3.75, as in the present case). In the example of the widthof a gypsum sample=1 cm, its density=1.32 g/cm³, the mass of the mixtureis 1.32 g. Thus, the share of the mass of tungsten particles in themixture is:1.32×0.05×0.75=0.0495 g,i.e., 3.75% of the total mass of the mixture. The mass of tungsten equalto the mass of a lead plate having a width of 0.04 cm (using the resultsof X-ray testing) is equal to0.04×0.75×19.3=0.347 g,which corresponds to 26.32% of the mixture's mass.

The above-stated examples of particular embodiments of X-ray absorbingmaterials and the ways of achieving these embodiments testify to theindustrial applicability of these materials in various areas ofengineering.

1. An X-ray absorbing material comprising: a matrix with a fixed X-rayabsorbing metal-containing filler in the form of dispersed particles,wherein said filler material is a poly-dispersed mixture that has beensegregated by intermixing and that contains metallic particles having asize between 10⁻⁹ and 10⁻³ m fixed in a textile base that serves as amatrix; and wherein the particles are bonded to the surface of andembedded in said textile base, and where the density of the X-rayabsorbing material as a whole, given that the X-ray absorbing propertiesare equal to those of the material used for the particles of the X-rayabsorbing filler, is defined by the relation:ρm=(0.01–0.20)ρp, where ρm is the density of the X-ray absorbingmaterial as a whole, and ρp is the density of the material used for theparticles of the X-ray absorbing filler.
 2. An X-ray absorbing materialcomprising: a matrix with a fixed X-ray absorbing metal-containingfiller in the form of dispersed particles, where said filler material isa poly-dispersed mixture that has been segregated by intermixing andthat contains metallic particles having a size between 10⁻⁹ and 10⁻³ m,wherein said particles are surrounded by the volume of a matrix that ismade of at least one compound that solidifies under atmosphericpressure, or made of a composition derived from a base of the samecompound, and the total mass of the segregated, poly-dispersed mixtureconsisting of particles of the X-ray absorbing filler is defined by therelation:M=(0.05–0.5) m, where M is the total mass of the segregatedpoly-dispersed mixture consisting of the X-ray absorbing fillerparticles, and m is the equivalent mass of the X-ray absorbing fillermaterial equal in protective properties to mass M.
 3. An X-ray absorbingmaterial comprising: a matrix with a fixed X-ray absorbingmetal-containing filler in the form of dispersed particles, where saidfiller material is a poly-dispersed mixture containing metallicparticles having a size between 10⁻⁹ and 10⁻³ m, wherein said particlesare bonded to an intermediate substrate surrounded by the volume of thematrix formed of at least one compound that solidifies under pressure.4. An X-ray absorbing material, as defined in claim 3, wherein: atextile base is used as an intermediate substrate.
 5. An X-ray absorbingmaterial, comprising: a matrix with a fixed X-ray absorbingmetal-containing filler in the form of dispersed particles, where saidfiller material is a poly-dispersed mixture containing metallicparticles having a size between 10⁻⁹ and 10⁻³ m, wherein said particlesare bonded to an intermediate substrate surrounded by the volume of thematrix formed of at least one compound that solidifies under pressure;and a mineral fiber is used as said intermediate substrate.
 6. An X-rayabsorbing material comprising: a matrix with a fixed X-ray absorbingmetal-containing filler in the form of dispersed particles, where saidfiller material is a poly-dispersed mixture containing metallicparticles having a size between 10⁻⁹ and 10⁻³ m, wherein said particlesare bonded to an intermediate substrate surrounded by the volume of thematrix formed of a composition derived from at least one compound thatsolidifies under pressure.